1. Field of the Invention
The present invention relates generally to the treatment of conditions in the oral cavity and more specifically to a delivery system for applying a preparation, e.g. bleach, desensitizing agent, anticariogenic agent, antimicrobial agent, fluoride, etc., to the surfaces of teeth.
2. Antecedent Technology
Significant advances in the art of tooth whitening have evolved in recent years. Tooth whitening is no longer relegated to the costly and time consuming procedures rendered by the dental practitioner. Various approaches have evolved for practicing tooth whitening procedures without participation of the dental practitioner.
Among the early tooth whitening systems for do-it-yourself usage was a paste or gel containing a hydrogen peroxide or carbamide peroxide constituent. The gel or paste was applied to tooth surfaces by, for example, a toothbrush, a cotton swab, etc.
Unfortunately, such systems failed to provide readily noticeable results, due to a combination of factors including the limited time duration of application as well as the dilution of effective whitening or bleaching constituent within the oral cavity by saliva. Further, gingival surfaces were engaged by the whitening or bleaching constituent, leading to possible gingival initiation or other undesired effects.
One approach at providing an effective delivery system for a tooth whitening preparation on buccal enamel surfaces of target teeth included the system disclosed in U.S. Pat. No. 5,611,687 which issued Mar. 18, 1997 to applicant herein. Such system comprised and applicator for carrying and applying a liquid preparation solely upon buccal surfaces of target teeth, i.e. teeth which are visible when talking, smiling, etc. The liquid preparation was drawn to an applicator tip by capillary action. To administer a coating of the tooth whitening preparation on selected tooth enamel surfaces, the tip was wiped over the surfaces to be treated. The efficacy of such delivery system was impeded, however because the liquid preparation was susceptible to saliva dilution.
Other attempts for improving the self administration of tooth whitening preparations included heating a dental tray retainer carrying a moldable material in boiling water, taking an impression of the user's dentition, applying a tooth whitening material to the internal surfaces of the impression and then wearing the custom fit retainer, as disclosed in U.S. Pat. No. 5,165,424 issued Nov. 24, 1992. The system disclosed therein did not attain widespread commercial success, perhaps due to the fact that the device involved difficult procedures and was more suited for implementation by a dental professional. Additionally, the custom fit retainer was bulky and cumbersome and impeded speech and appearance could not, therefore, be worn in any environment wherein social encounters might be anticipated.
A further approach comprised the utilization of flexible strips preloaded with a tooth whitening preparation, as disclosed in U.S. Pat. No. 5,891,453 issued Apr. 6, 1999. The flexible strips disclosed therein were unable to attain a true impression of the user's buccal dentition; they could not intimately enter interdental crevices, for example. Further, the user was not able to control the concentration of tooth whitening preparation or limit the application to selected target teeth or tooth surfaces. A further disadvantage was that the tooth whitening preparation was often in contact with gingival surfaces, which led to gingival irritation.